Interpretive Summary: Various formulations of a synthetic sex pheromone of codling moth have been developed in order to manage this pest in apple and pear orchards. The most common use of sex pheromones has been with hand-applied dispensers, but their application is labor intensive and growers are interested in alternative approaches. Sprayable microencapsulated formulations have been developed but were found not to be very effective. Researchers at USDA, ARS in Wapato, WA developed a new approach where the formulation was concentrated and applied in a low volume of water. This method dramatically increased the number of microcapsules deposited in the canopy and increased their clustering on leaves. Studies developed an effective sprayer pulled by an ATV to quickly apply the low-volume pheromone spray. Field studies demonstrated that the low-volume spray was more effective than the previous high-volume application and provided seasonal control of codling moth similar to hand-applied dispensers. This new approach is now marketed by the manufacturer and provides growers with a viable alternative to the use of hand-applied dispensers and a new tool to supplement existing programs during peak pest periods and in locations with high pest pressure.

Technical Abstract:
The application of a microencapsulated (MEC) sex pheromone formulation (Checkmate® CM-F) for codling moth, Cydia pomonella (L.), in low volume, concentrated sprays was evaluated in a series of small plot and grower trials in apple and pear. Preliminary tests found that MEC sprays applied at 172-207 kilopascals in 12 to 23 liters ha-1 deposited the highest density of microcapsules per leaf. The addition of a latex sicker did not increase the deposition of microcapsules. Small-plot tests in 2004 compared the effectiveness of two low-volume sprayers against a standard high-volume spray (926 liters ha-1) applied at 1,379 kilopascals. Moth catches and fruit injury were significantly lower in plots treated with the low-volume sprays compared to plots treated with the standard sprayer. Larger trials were conducted with a low-volume sprayer in 4-ha plots within apple (2005-06) and pear orchards (2005) paired with similar plots treated with pheromone dispensers. Levels of fruit injury were not significantly different between pheromone treatments in any of the three tests. However, moth catches were significantly higher in the MEC- versus the dispenser-treated plots, particularly during the first generation. No difference was found in the fruit injury levels but moth catches were significantly higher in sprayed apple orchards irrigated with overhead versus undertree systems.